In Thursday's game against the Maple Leafs, Kovalchuk put home the winner with 24 seconds left in overtime and he did it with 3:59 left in the third on Friday to help the Devils win a fourth straight game.
Brian Rolston tied the game on the power play 9:12 into the third, while Johan Hedberg made 31 stops for the Devils, who are 12-1-2 over their last 15 games.
Patrick Marleau scored the lone goal and Antti Niemi made 21 stops for the Sharks, who had a season-high five-game winning streak stopped.
All of the scoring happened in the third period as the Sharks took the initial lead in the frame when a shot fromNiclas Wallin at the left point was stopped and Marleau banged home the rebound from the right side 6:08 in.
New Jersey, though, tied the game three minutes later on a 4-on-3 power play as a pass from Kovalchuk at the outside left circle went to the high slot where Rolston used a big one-timer to beat Niemi.
In a repeat of Thursday, Kovalchuk again provided the heroics as the Devils won a faceoff at the right circle and his turnaround shot from the outside squeezed between the pads of Niemi.
Torrey Mitchell was called for a high-sticking double minor for fouling Dainius Zubrus with 2:19 to play and New Jersey was able to kill off the clock for the win.
Hedberg stopped 24 shots over the first 40 minutes while Niemi was only tested 11 times in that span.
The Devils have off until next Wednesday when they will host Carolina...San Jose continues its seven-game road trip at Florida on Sunday...New Jersey has won four of the last five aginast San Jose. Also, the Sharks have lost five straight in the Garden State and haven't won there since Nov. 14, 2000.